The present invention relates to digital signal processing in audio-video systems such as television receivers (with or without a display device) and set-top boxes such as digital satellite receivers.
Recording of audio-video signals, for example using a video cassette recorder (VCR), is common practice. Recording is useful when the viewer wants to watch a program later at a convenient time. When the recording is played back, the viewer can select the parts of the program he wants to see, or playback can be interrupted at any time, e.g. to answer a telephone call. However, when viewing a program as it is received, the viewer cannot interrupt the program. Talking to someone or leaving the room, may prevent a viewer from viewing part of a program being received in xe2x80x9creal timexe2x80x9d (i.e., not recorded on video tape) such as from a broadcast satellite signal provider, a broadcast television station, or a cable television source.
The foregoing problems are overcome by providing a method for processing a received video signal representing a video program comprising the steps of processing digital data representing a portion of the video program occurring during a first interval for producing a first signal component; the first signal component representing the portion of the video signal compressed in time; providing an output signal having the first signal component during a second interval; and replacing the first signal component in the output signal with a second signal component representing the input video signal in response to the end of the second interval.
In accordance with an aspect of the invention, the first signal component is included in the output signal during a playback mode of operation and new time-compressed information continues to be stored during playback mode. Output of the time compressed information during playback mode occurs at a rate faster than the rate at which new data is stored. A point in time at which data being output is the same as data being stored is detected as indicating the end of the second interval and the first signal component is automatically replaced by the second signal component in the output signal in response to detection of the end of the second interval.
The invention may be implemented in a system for producing an output signal representing a multi-picture image during a multi-picture display mode of operation. The output signal is suitable for coupling to a display device for simultaneously displaying first and second image regions. The first signal component is displayed in a first image region and the second signal component is displayed in the second image region. Activation of the playback mode automatically activates the multi-picture display mode and the multi-picture display mode automatically terminates in response the end of the second interval.
Another aspect of the invention involves automatically modifying display characteristics in response to activation of the playback mode of operation.